Holding negative beliefs about aging can affect your aging experience. According to The Baltimore Longitudinal Study of Aging, if you believe your memory will decline as you get older, it will.
You can read about it here.

This study shows that the adverse influence of negative self-stereotypes on cognitive performance is not limited to a short-term laboratory effect. Rather, the findings demonstrate, for the first time, that stereotypes also predict memory performance over an extended period in the community.

In countries that do not have negative beliefs about aging, such as India and China, the elderly do not age related memory decline. Watch your thoughts and believe you will get better as you get older. It’s up to you!